Fleeting Magnetism And OneWord: Plastics

Fleeting Magnetism

Eighteen months ago, China threatened to restrict exports of rare-earth metals, such as neodymium, used in the AC permanent-magnet motors powering the Nissan Leaf, Toyota Prius, and Chevrolet Volt. That prompted carmakers to explore alternatives. The most obvious candidate, already part of GM’s eAssist mild-hybrid system, is an AC induction motor containing no permanent magnets. (In an induction motor, static electric coils induce magnetism in a rotor made of steel laminations instead of permanent magnets.) While induction motors are slightly less efficient, they’re notably lighter, cheaper, and well suited to moderate-load, short-duration duty. The GM design shown here (ironically made in China), contributes more than 100 pound-feet of torque to curtail downshifts during passing and hill climbing.

OneWord: Plastics

 The trickledown from Formula 1 to road cars of ultralight, ultrastiff composites is migrating beyond carbon-fiber-reinforced tubs and body panels into suspension and powertrain domains. ZF’s experimental molded-plastic front and rear suspension systems cut both weight and parts count. Florida-based Composite Castings has produced a few four-cylinder engine blocks made of carbon-fiber-reinforced epoxy, saving 20 pounds over a comparable aluminum block. And an Australian firm, Carbon Revolution, has introduced the first single-piece carbon-fiber wheel that, in a 12.5-by-20-inch size, is 40 percent lighter than an aluminum wheel.